Plane Of Aromatic Ring Research Articles

Ethane-1,2-diyl bis(pyridine-3-carboxylate)

The title compound, C14H12N2O4, has twofold imposed crystallographic symmetry in the solid state. The asymmetric unit contains one half-mol­ecule. An intra­molecular C—H⋯O hydrogen bond is formed between the carboxyl­ate O group and one H atom of the aromatic ring such that a five-membered ring is formed. The angle between the planes of symmetry-related aromatic rings is 44.71 (19)°.

(E)-N-[4-(Methylsulfonyl)benzylidene]aniline

The mol­ecule of the title compound, C14H13NO2S, displays a trans configuration with respect to the C=N double bond. The dihedral angle between the two aromatic ring planes is 62.07 (18)°.

(E)-2-Methyl-N-[4-(methylsulfonyl)benzylidene]aniline

Mol­ecules of the title compound, C15H15NO2S, display an E configuration with respect to the C=N double bond. The crystal structure is stabilized by weak C—H⋯O hydrogen bonds. The dihedral angle between the two aromatic ring planes is 50.41 (12)°.

2-Amino-4-methylbenzenesulfonamide

In the crystal of the title compound, C7H10N2O2S, the mol­ecules are linked by two strong N—H⋯O hydrogen bonds. The mol­ecular structure is stabilized by an intra­molecular N—H⋯O hydrogen bond. The C/S/N plane makes a dihedral angle of 69.7 (2)° with the aromatic ring plane.

(1E,4E)-1,5-Bis(2,4-dimethylphenyl)penta-1,4-dien-3-one

In the title compound, C21H22O, a derivative of the biologically active compound curcumin, the dihedral angle between the aromatic ring planes is 20.57 (11)°.

A second polymorph of (2E)-1-(4-fluorophenyl)-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one

The crystal structure of the title compound, C18H17FO4, reported here is a polymorph of the structure first reported by Patil et al. [Mol. Cryst. Liq. Cryst. Sci. Technol. Sect. A (2007), 461, 123–130]. It is a chalcone analog and consists of substituted phenyl rings bonded at the opposite ends of a propenone group, the biologically active region. The dihedral angle between the mean planes of the aromatic rings within the 4-fluoro­phenyl and trimethoxy­phenyl groups is 28.7 (1)° compared to 20.8 (6)° in the published structure. The angles between the mean plane of the prop-2-ene-1-one group and the mean plane of aromatic rings within the 4-fluoro­phenyl and trimethoxy­phenyl groups are 30.3 (4) and 7.4 (7)°, respectively, in contast to 10.7 (3) and 12.36° for the polymorph. While the two 3-meth­oxy groups are in the plane of the trimeth­oxy-substituted ring, the 4-meth­oxy group is in a synclinical [−sc = −78.1 (2)°] or anti­clinical [+ac = 104.0 (4)°] position, compared to a +sc [53.0 (4)°] or −ac [−132.4 (7)°] position. While no classical hydrogen bonds are present, weak inter­molecular C—H⋯π-ring inter­actions are observed which contribute to the stability of the crystal packing. The two polymorphs crystallize in the same space group, P21/c, but have different cell parameters for the a, b and c axes and the β angle. A comparison of the mol­ecular geometries of both polymorphs to a geometry optimized density functional theory (DFT) calculation at the B3-LYP/6–311+G(d,p) level for each structure provides additional support to these observations.

Synthesis, crystal structure, spectral and thermal characterization of bis( o-vanillinato)-triethylenglycoldiiminecopper(II) and bis[(R)-(−)-hydroxymethylpropylimine o-vanillinato]copper(II)

The novel complexes bis( o-vanillinato)-triethylenglycoldiiminecopper(II) ( 1) and bis[(R)-(−)-hydroxymethylpropylimine o-vanillinato]copper(II) ( 2) have been synthesized and characterized by elemental analysis, magnetic susceptibility, spectral methods (UV–Vis and FT-IR), simultaneous TG, DTA techniques and X-ray diffraction. The crystal structure of ( 1) determined that the Cu atom is coordinated by two imine N atoms and two phenol O atoms from the Schiff base ligand in a slightly distorted square-planar coordination. The o-vanillinato ligands moieties of the molecule are in a trans configuration and the dihedral angle between the aromatic ring planes is 43.97(14)°. Compound ( 2) crystallizes in the triclinic space group P 1 ¯ with unit-cell parameters a = 8.054(7), b = 8.684(7), c = 10.258(8) Å, α = 79.452(6)°, β = 70.454(6)°, γ = 65.427(6)° and Z = 1. The crystal structure of ( 2) has indicated that the complex is slightly distorted square planar and is chelated by the two imine N atoms and two phenol O atoms from the Schiff base ligand. The o-vanillinato ligands moieties of ( 2) are in a trans configuration and the torsion angle between the aromatic ring planes is 60.5(3)°. The crystal packing involves both hydrogen-bonding and C–H⋯π interactions. Thermal analyses showed that the title compounds decompose in two stages over the temperature range 20–1000 °C in a static air atmosphere.

(2E)-3-(3-Bromophenyl)-1-(4-chlorophenyl)prop-2-en-1-one: a non-merohedral twin

In the title compound, C15H10BrClO, the mol­ecule adopts an E configuration with respect to the C=C double bond and the dihedral angle between the aromatic ring planes is 3.98 (16)°. In the crystal, inversion dimers linked by pairs of C—H⋯O bonds are seen and weak π–π stacking [centroid–centroid separation = 3.8776 (19) Å] may further consolidate the structure. The crystal studied was a non-merohedral twin with a ratio of the twin components of 0.9093 (13):0.0907 (13). The twin operation is a twofold rotation around c*.

1,4-Bis(4-nitrostyryl)benzene

The complete molecule of the title compound, C22H16N2O4, is generated by a crystallographic centre of inversion. The plane of the central aromatic ring is tilted by 11.85 (4)° with respect to the outer aromatic ring. The crystal packing is determined by van der Waals inter­actions, with stair-like stacking between adjacent aromatic rings. The stacks are staggered and each layer is approximately 3.8 Å from the next. The closest inter­molecular contact (approximately 2.42 Å) is between an O atom and a vinyl H atom.

Substrate Specificity, Inhibitors and Regulation of Human Cytochrome P450 2D6 and Implications in Drug Development

CYP2D6 accounts for only a small percentage of total hepatic CYPs (<2%), but it metabolizes approximately 25% of clinically used drugs (>100) with significant polymorphisms. A number of drugs acting on the central nervous system and cardiovascular system are substantially metabolized by CYP2D6. The enzyme also utilizes hydroxytryptamines and neurosteroids as endogenous substrates. In addition, CYP2D6 metabolizes procarcinogens and neurotoxins such as 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, 1,2,3,4-tetrahydroquinoline, and indolealkylamines. Typical CYP2D6 substrates are usually lipophilic bases with a planar hydrophobic aromatic ring and a nitrogen atom which can be protonated at physiological pH, but several atypical substrates such as spirosulfonamide and pactimibe do not contain a basic nitrogen atom. The structure of human CYP2D6 has been recently determined and shows the characteristic CYP fold as observed in other members of the CYP superfamily, with a well-defined active site cavity above the heme group with a volume of approximately 540 A(3). CYP2D6 is largely uninducible by prototypical CYP inducers such as phenobarbital, rifampin and dexamethasone, but it is regulated by hepatocyte nuclear factor-4alpha, a nuclear receptor. CYP2D6 is subject to inhibition by a number of drugs and this may provide an explanation for numerous clinical drug interactions. CYP2D6 has an important role in drug development and it is a common practice for pharmaceutical industry nowadays to a great extent screen drug candidates early in development as possible CYP2D6 substrates and/or inhibitors and drop such candidates where they have alternatives. This candidate selection might eventually lead to a less prominent role of this enzyme in the future for drug metabolism and less interindividual variability in drug exposure and minimize potentially adverse drug interactions. Further studies are warranted to delineate the molecular mechanisms involved in the function and regulation of CYP2D6.

Adsorption structure of phenylphosphonic acid on an alumina surface

The adsorption structure of phenylphosphonic acid (PPOA) on an alumina surface was investigated as a function of exposure and temperature using infrared reflected absorption spectroscopy (IRAS) and a Kelvin probe. The alumina surface was held at room temperature during deposition. At monolayer adsorption, P O and Phenyl-P bands are observed, which indicate the creation of P O Al bonds. The aromatic ring plane is positioned perpendicular to the surface, i.e. deprotonated PPOA stands vertically on the surface. At multilayer adsorption, P O and P OH bands appear in the spectra. The multilayer PPOA film starts to desorb at 400 K. From 400 to 700 K, the IRAS spectra are similar to the monolayer spectrum, indicating that the multilayer structure reverses to the monolayer-like PPOA adlayer by heating. The acid molecules start to desorb at 700 K.

Bis(2-chlorobenzyl)dimethylammonium bromide

In the title compound, C16H18Cl2N+·Br−, the dihedral angle between the aromatic ring planes is 57.73 (5)°. In the absence of any strong hydrogen bonds, the structure results from a large number of competing weaker inter­actions including Cl⋯Cl [3.4610 (5) Å] and C—H⋯Cl contacts and both (aryl) C—H⋯Br and N+—Csp 3—H⋯Br− cation–anion inter­actions.

2,6-Bis(2-hydroxyethyl)-8b,8c-diphenylperhydro-2,3a,4a,6,7a,8a-hexaazacyclopenta[def]fluorene-4,8-dithione

In the title mol­ecule, C24H28N6O2S2, the dihedral angle between the aromatic ring planes is 42.2 (1)°. In the crystal structure, the hydr­oxy groups are involved in O—H⋯S hydrogen bonding, which links the mol­ecules into corrugated layers propagating parallel to the bc plane.

2-(3-Chloroanilino)pyridine

In the title compound, C11H9ClN, the dihedral angle between the aromatic ring planes is 44.2 (1)° and the bridging C—N—C bond angle is 127.60 (19)°. The amino N—H grouping makes a hydrogen bond to the pyridyl N atom of an adjacent mol­ecule across a center of inversion, generating a hydrogen-bonded dimer.

Diethyl (1-hydroxy-1,2-diphenylethyl)phosphonate

In the title compound, C18H23O4P, the dihedral angle between the aromatic ring planes is 69.94 (14)°. Both ethyl side chains are disordered over two sets of sites, with occupancy ratios of 80:20 and 70:30. In the crystal, inversion dimers linked by pairs of O—H⋯O hydrogen bonds occur, leading to R 2 1(8) loops, and C—H⋯O and weak C—H⋯π inter­actions are also seen.

2-(4-Methylphenyl)-1H-anthraceno[1,2-d]imidazole-6,11-dione: a fluorescent chemosensor

In the title compound, C22H14N2O2, the five rings of the mol­ecule are not coplanar. There is a significant twist between the four fused rings, which have a slightly arched conformation, and the pendant aromatic ring, as seen in the dihedral angle of 13.16 (8)° between the anthraquinonic ring system and the pendant aromatic ring plane.

N-Phenylanthranilic anhydride

The complete mol­ecule of the title compound, C26H20N2O3, is generated by crystallographic twofold symmetry, with the central O atom lying on the rotation axis. The conformation is stabilized by an intra­molecular N—H⋯O hydrogen bond. The dihedral angle between the inner and outer aromatic ring planes is 61.12 (5)°.

(E)-2,3-Bis(4-methoxyphenyl)acrylic acid

In the title mol­ecule, C17H16O4, the angle between the aromatic ring planes is 69.1 (6)°. The crystal structure is stabilized by inter­molecular O—H⋯O hydrogen bonds; mol­ecules related by a centre of symmetry are linked to form inversion dimers.

(2R)-2-Benzenesulfonamido-2-phenylethanoic acid

In the title compound, C14H13NO4S, the dihedral angle between the aromatic ring planes is 45.52 (18)°. In the crystal structure, inter­molecular N—H⋯O and O—H⋯O hydrogen bonds lead to chains of mol­ecules propagating in [100] in which the the ring motifs R 2 1(8), R 2 2(8) and R 3 3(11) are apparent. These polymeric chains are linked through C—H⋯O inter­actions.

5-Benzene-sulfonamido-2-chloro-benzoic acid.

In the title compound, C13H10ClNO4S, the dihedral angle between the aromatic ring planes is 87.07 (6)° and an intra­molecular C—H⋯O inter­action occurs. In the crystal, inversion dimers linked by two O—H⋯O hydrogen bonds arise from the carboxyl groups. N—H⋯O hydrogen bonds link the dimers into chains and short C—Cl⋯π and S—O⋯π contacts are also seen.